Keywords
Windbreaks
In situ measurements
Dike
Nord-Pas-de-Calais
France
How to Cite
Abstract
The shoreline of Dunkirk Seaport partly consists of a macrotidal beach oriented WSW-ENE backed by a 6 km long coated dike called "digue du Braek†. Aeolian sand transport was estimated on asphalt by means of sand traps. Also, time-averaged wind speed profiles were measured using cup anemometers under various wind velocities and directions along a transversal profile on the dike and the upper beach. High rates of sand transport enabled the setup of different kinds of experimental windbreaks on asphalt, in order to test potential dune formation on this kind of substrate. Under oblique onshore winds, it was regularly observed that amounts of sand captured in the traps placed on the dike were more important than those in traps placed on the upper beach. These results were related to sand sources: windblown sand captured on the dike originated from the coastal dunes developed at the dike toe, while sand trapped on the upper beach came from the tidal zone were aeolian transport is limited by complex intertidal bar-trough topography. It also appeared from the topographic surveys carried out on the windbreaks that although their location seemed to play a major role on the amount of sand captured, fences and synthetic fabrics deployed on sandy surfaces were also able to trap windblown sand on the seaport dike.References
Anthony, E.J., M-H. Ruz, and S. Vanhée. 2009. Aeolian sand transport over complex intertidal bar-trough beach topography, Geomorphology, 105, 95-105.http://dx.doi.org/10.1016/j.geomorph.2007.12.013
Anthony, E.J., S. Vanhee, M-H. Ruz. 2007. An assessment of the impact of experimental brushwood fences on foredune sand accumulation base don digital elevation models. Ecological Engineering, 31, 41-46.http://dx.doi.org/10.1016/j.ecoleng.2007.05.005
Bagnold, R.A. 1941. The physics of blown sand and desert dunes. Chapman and Hall (Ed.), London, 265 p.
Bauer B.-O., R.G.D. Davidson-Arnott, 2002. A general framework for modeling sediment supply to coastal dune including wind angle, beach geometry and fetch effects. Geomorphology, 49, p. 89-108.http://dx.doi.org/10.1016/S0169-555X(02)00165-4
Bauer B.O., R.G.D. Davidson-Arnott, K.F. Nordstrom, J. Ollerhead, N.L. Jackson. 1996. Indeterminacy in Aeolian Sediment Transport Across Beaches. Journal of Coastal Research,12 (3), 641-653.
Belly P.Y. 1964. Sand movement by wind. US Army Corps of Engineers, Coastal Engineering Research Center, Tech. Memo., 1, Washington D.C., 38 p.
Cartier, A., Héquette, A., 2011. Variation in longshore sediment transport under low to moderate conditions on barred macrotidal beaches. Journal of Coastal Research SI (ICS 2011), 45 - 49.
Christiansen M.B., R.G.D. Davidson-Arnott. 2004. Rates of landward sand transport over the foredune at Skallingen, Denmark and the role of dune ramp. Danish Journal of Geography, 104 (1), 31-43.
Davidson-Arnott, R.G.D., K. MacQuarrie, T. Aagaard, 2005. The effect of wind gusts, moisture content and fetch length on sand transport on a beach. Geomorphology, 68, 115-129.http://dx.doi.org/10.1016/j.geomorph.2004.04.008
Davison, A.T., R.J. Nicholls, S.P. Leatherman, 1992. Beach nourishment as a coastal management tool: an annotated bibliography on developments associated with the artificial nourishment of beaches. Technical communication. Journal of Coastal Research, 8, 984-1022.
Draga, M., 1983. Eolian activity as a consequence of beach nourishment - observations at Westerland (Sylt), German North Sea coast. Zeitschrift fur Geomorphologie, Supplement 45, 303-319.
Eitner, V., G. Ragutski, 1994. Effects of artificial beach nourishment on nearshore sediment distribution (Island of Norderney, Southern North Sea). Journal of Coastal Research, 10, 637-650.
Grafals-Soto, R., 2012. Effects of sand fences on coastal dune vegetations distribution. Geomorphology, 145-146, 45-55.http://dx.doi.org/10.1016/j.geomorph.2011.12.004
Grafals-Soto, R., K.F. Nordstrom, 2009. Sand fences in the coastal zone: intended and unintended effects. Environmental Management, 44, 420-429.http://dx.doi.org/10.1007/s00267-009-9331-7
PMid:19629579
Héquette, A., M-H. Ruz, D. Marin, V. Sipka, 2012. Suivi morpho-sédimentaire de l'UG4. Rapport annuel 2011. Laboratoire LOG, ULCO, 45p.
Hesp P.A., R.G.D. Davidson-Arnott, I.J. Walker, J. Ollerhead 2005. Flow dynamics over a foredune at Prince Edward Island, Canada. Geomorphology, 65, 71-84.http://dx.doi.org/10.1016/j.geomorph.2004.08.001
Jackson N.L., K.F. Nordstrom. 2011. Aeolian sediment transport and landforms in managed coastal systems : a review. Aeolian research, 3(2), 181-196.
Mendelssohn, I.A., M.W. Hester, F.J. Monteferrante, F. Talbot, 1991. Experimental dune building and vegetative stabilization in a sand-deficient barrier island setting on the Louisiana coast, USA. Journal of Coastal Research 7, 137-149.
Miller, D.L., M. Thetford, L. Yager, 2001. Evaluating sand fence and vegetation for dune building following overwash by Hurricane Opal on Santa Rosa Island, Florida. Journal of Coastal Research 17, 936-948.
Meur-Ferec C., M-H. Ruz. 2002. Transports éoliens réels et théoriques en haut de plage et sommet de dune (Wissant, Pas-de-Calais, France). Géomorphologie,4, 321-334.http://dx.doi.org/10.3406/morfo.2002.1155
Nickling W.G., C. McKenna Neuman. 1997. Wind tunnel evaluation of a wedge-shaped Aeolian sediment trap. Geomorphology, 18, 333-345.http://dx.doi.org/10.1016/S0169-555X(96)00040-2
Nickling, W. G. and Davidson-Arnott, R. G. D. 1990. Aeolian sediment transport on beaches and coastal dunes, in Arnott, R.G. D. (Ed.), Proceedings of the Symposium on Coastal Sand Dunes, National Research Council, Ottawa, 1-35.
Nordstrom, K.F., R. Lampe, L.M. Vandemark, 2000. Re-establishing naturally functioning dunes on developed coasts. Environmental Management, 25 (1), 37-51.http://dx.doi.org/10.1007/s002679910004
PMid:10552101
Nordstrom, K.F., S.M. Arens. 1998. The role of human actions in evolution and management of foredunes in the Netherlands and New Jersey, USA. Journal of Coastal Conservation, 4, 169-180.http://dx.doi.org/10.1007/BF02806509
Ruz, M-H., E.J. Anthony. 2008. Sand trapping by brushwood fences on a beach-foredune contact : the primacy of the local sediment budget. Zeitschrift fur Geomorphology, 52 (3), 179-194.http://dx.doi.org/10.1127/0372-8854/2008/0052S3-0179
Svasek J.N., J.H.J. Terwindt, 1974. Measurements of sand transport by wind on a natural beach. Sedimentology, 21, 311-322.http://dx.doi.org/10.1111/j.1365-3091.1974.tb02061.x
Tresca, A., M-H. Ruz, P. Gregoire. 2012. Caractérisation du transport éolien sur asphalte à partir de piégeages in situ : le cas de la digue du Braek, Dunkerque. Paralia, Actes colloque JNGCGC 2012 Cherbourg, 503-510.
Van der Wal, D., 2004. Beach-dune interactions in nourishment areas along the Dutch coast. Journal of Coastal Research, 20, 317-325.http://dx.doi.org/10.2112/1551-5036(2004)20[317:BIINAA]2.0.CO;2
Walker I.J., R.G.D. Davidson-Arnott, P.A. Hesp, B.O. Bauer, J. Ollerhead 2009. Mean flow and turbulence responses in airflow over foredunes: new insights from recent research. Journal of Coastal Research SI n° 56, pp 366-370.
Walker, I.J., Hesp, P.A. (in press). Fundamentals of Aeolian Sediment Transport: Airflow over dunes. Ch. 11.7, Vol. 11: Aeolian Geomorphology, Treatise on Geomorphology. Elsevier: Oxford.